/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 2001-2006 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: UnionIterator.java,v 1.5 2005/09/28 13:48:38 pvedula Exp $
 */

package com.sun.org.apache.xalan.internal.xsltc.dom;

import com.sun.org.apache.xalan.internal.xsltc.DOM;
import com.sun.org.apache.xalan.internal.xsltc.runtime.BasisLibrary;
import com.sun.org.apache.xml.internal.dtm.DTMAxisIterator;
import com.sun.org.apache.xml.internal.dtm.ref.DTMAxisIteratorBase;

/**
 * UnionIterator takes a set of NodeIterators and produces
 * a merged NodeSet in document order with duplicates removed
 * The individual iterators are supposed to generate nodes
 * in document order
 *
 * @author Jacek Ambroziak
 * @author Santiago Pericas-Geertsen
 */
public final class UnionIterator extends MultiValuedNodeHeapIterator {

  /**
   * wrapper for NodeIterators to support iterator
   * comparison on the value of their next() method
   */
  final private DOM _dom;

  private final class LookAheadIterator
      extends MultiValuedNodeHeapIterator.HeapNode {

    public DTMAxisIterator iterator;

    public LookAheadIterator(DTMAxisIterator iterator) {
      super();
      this.iterator = iterator;
    }

    public int step() {
      _node = iterator.next();
      return _node;
    }

    public HeapNode cloneHeapNode() {
      LookAheadIterator clone = (LookAheadIterator) super.cloneHeapNode();
      clone.iterator = iterator.cloneIterator();
      return clone;
    }

    public void setMark() {
      super.setMark();
      iterator.setMark();
    }

    public void gotoMark() {
      super.gotoMark();
      iterator.gotoMark();
    }

    public boolean isLessThan(HeapNode heapNode) {
      LookAheadIterator comparand = (LookAheadIterator) heapNode;
      return _dom.lessThan(_node, heapNode._node);
    }

    public HeapNode setStartNode(int node) {
      iterator.setStartNode(node);
      return this;
    }

    public HeapNode reset() {
      iterator.reset();
      return this;
    }
  } // end of LookAheadIterator

  public UnionIterator(DOM dom) {
    _dom = dom;
  }

  public UnionIterator addIterator(DTMAxisIterator iterator) {
    addHeapNode(new LookAheadIterator(iterator));
    return this;
  }
}
